"Google is making another attempt to fix the Android update problem at the Google I/O conference. The plan is to give smartphone, tablet and chip manufacturers earlier opportunities to adapt their current and new hardware to forthcoming Android versions. Google said that it hopes that this will allow users to receive their updates faster. To achieve this, Android executive Hugo Barra announced a 'Platform Development Kit'." I have my doubts.

Google should accept the fact that skins do and will exist and instead of producing useless gimmicks such as face unlock, focus on working out stable api to support both OEM and carrier customization while making the core *separately* upgradeable. Effect: stable, easily upgradeable products.
They are not consumer product company and should focus on what makes Android strong (app api, core services, google apps) while fixing stuff where it's weak (UI performance, modularity).

As for HW variances, they should work with both OEMS and carriers to cluster the whole hw zoo into several manageable chunks (say, around soc baseline platforms) that function identically on lowest level, and push exactly the same kernels to carrier validation for each of them. The point is, it's really not a carrier job to validate, say a camera, LCD or accelerometer so why should it increase overall phone variation?